Rescue teams on Monday sifted through rubble of flattened multistory buildings to try to reach dozens of people believed trapped beneath after a 7.2-magnitude earthquake struck eastern Turkey. The Interior Minister said the death toll in the powerful quake has increased to 217.

Hundreds of rescue teams worked throughout the night searching for survivors among dozens of pancaked buildings, as aid groups scrambled to set up tents, field hospitals and kitchens to assist thousands left homeless.

Interior Minister Idris Naim Sahin said about 80 multistory buildings collapsed in the city of Ercis alone when the earthquake struck Sunday. He said some 40 buildings still had people trapped inside, giving rise to fears that the death toll could increase substantially. The minister did not give any estimates.

"Rescue work is ongoing, especially at buildings where (rescuers) have determined survivors," Sahin said.

The hardest-hit area was Ercis, an eastern city of 75,000 close to the Iranian border and on one of Turkey's most earthquake-prone zones. The bustling city of Van, about 55 miles (90 kilometers) south of Ercis, also sustained substantial damage. Highways in the area caved in.

Sahin said 117 were killed in Ercis, another 100 died in Van while some 740 people were injured.

U.S. scientists recorded over 100 aftershocks in eastern Turkey within 10 hours of the quake, including one with a magnitude of 6.0.

Authorities advised people to stay away from damaged homes, warning they could collapse in the aftershocks.

Residents spent the night outdoors and lit campfires, while the Red Crescent began setting up tents in a stadium. Others sought shelter with relatives in nearby villages.

Rescue efforts went deep into the night under generator-powered floodlights. Workers tied steel rods around large concrete slabs in Van, then lifted them with heavy machinery.

Around 1,275 rescue teams from 38 provinces were being sent to the region, officials said, and troops were also assisting search-and-rescue efforts.